Thermoelectric battery



June 8 1926.

G. DUCH THERMOELECTRIC BATTERY Filed April 24, 1925 2 sheets-sheet June8 1926.

G. DUCH THERMOELECTRIC BATTERY Filed April 24, 1925 2 Sheets-Sheet 2 fsaPatented June 8, 1926.

UNITED STATES PATENT OFFICE.

GABRIEL DUCH, 0F LYON, FRANCE.

THERMOELECTBIC BATTERY.

aplicaran mea April 24, 1925, serial No. 25,541, and in France June 2o,1924.

The present invention relates to a thermoelectric battery adapted toabsorb the heat contained in hot gases and of transforming apart thereofinto electricity. The battery is more particularly adapted for use withwireless telegraphy apparatus in place of the usual heavy and cumbersomeaccumulators. Thus low tension batteries of light weight and small sizecan be constructed and used, for example, for heating the filaments ofthermionic valves used in wireless telegraphy and high tensionlbatteries for use in feeding plates of such valves.

The annexed drawing illustrates an example of construction of theinvention.

Fig. 1 is a diagrammatic plan View of an ele-ment of the battery,

Fig. 2 is a diagrammatic View in elevatlon showing the connectionsbetween a series of elements, o n i Fig. 3 is a diagrammatlc view 1nvertical section of a battery without its casing,

Fig. 4 is a diagrammatic View in vertical section of a battery providedwith its various accessories,

Fig. 5 is a graph illustrating the variations of the electromotive forceof a battery in function of the internal mean temperature of the hotelements.

Fig. 6 is a rgraph illustrating the variations of the differences ofpotential at the terminals of the battery.

The battery is constructed at follows Along radii of a circle a shown indotted lines in Fig. 1 alternating with one another are a series ofrectilinear wires b c constructed of two thermo-electric metals andarranged in such a way that for each wire one of the ends bears on thecircle a and the other on the circle ci concentric with the circle a.The wires b are shown in full lines and the Wires c in dotted lines.

The ends of the wires bearing on the circle la are soldered or connectedin pairs, the end of wire c with that of b2 that of c2 with that of bsand so on; it is the same for the wire ends bearing on the circle d, theeX- tremity of wire b is soldered to the end of wire c, the end of wireb2 with that of c2 and so on. Thus all these couples are associatedelectrically in series.

On the circle a are the wire ends b and e8 which are free and providedwith terminals e f.

A series of these wire crowns or rings g k i etc. so vformed (Fig. 3)are employed and separated by concentric washers j made of annanthus orother heat insulating substance y' in such a way that the connections Ysituated on the circle a extend beyond the said washers for a greaterlength than the connections situated on the circle al.

In order to nullify the effect of self-induction in the whole, thecrowns or rings in equal number are arranged face to face 1n such a waythat the-terminals corresponding to the different metals lie one abovethe other, respectively, the terminal f below the terminal e2 etc. Theseterminals are connected in pairs f with e2, f2 with e3 etc. Theremaining terminals e and f4 constitute the terminals of the battery.

The whole forms as it were a heat conduit comprising interior andexterior thermoelectric couples. If hot gases are passed through theaxial conduit fm, the couples operate to cool these gases and transmit'the caloriic energy produced, while transforming it partially intoelectric energy available at the poles. The gases circulate in thecylinder m formed by the superposed amianthus Washers and also in. thefree spaces in the wire ring elements.

It is to be remarked that by connecting l or soldering the terminals ofthe rings or crowns in parallel instead of in series, relatively highintensity can be induced with feeble electro-motive forces. Variouscombinations of parallel series of connections of the crowns arepossible according to the use to which the apparatus is to be put.

Further, air can enter between the amianthus washers and the wires ofthe rings and operates to complete the combustion of the gases if thelatter is not complete and at the same time contributes to the coolingof the exterior wire connections.

Fig. 4 shows a battery formed of the superposed crowns or rings; at thebase of the axial conduit mis a combustion chamber n in the form of adivergent cone and constructed of amianthus; in the axis of this conduitis a cylinder o of low heat conductivit and of low specific heat andintended to rive back the hot gases towards the crowns and to act byradiation on the hot surface. The gases escape through the divergentcone p.

Two triangular plates g and 7' connected by three rods s set at 120 toone another 1 from top to bottom in the vertical channels having asection in the form of a sector of an annulus generated by theconductors constituting the crowns.

The apparatus represented in Fig. 4 comprises a plate t carryingterminals in electric communication with the terminals of the crowns andallowing for all combinations in series or in parallel of the crowns ofthe battery.

The metals elnployed may be either iron and constantan, pr constantanand silver manganese alloy or wire drawn thermoelectrie metals such asare used particularly in the manufacture of pyrometers.

Further the hot gases necessary for the functioning ofthe apparatuscould be provided by the exhaust from the internal combustion engine ofa motor car, aeroplane or the like or from any other source of heat.

` The apparatus acts on the principle of cooling flames by metallicfabrics; the Wire couples extending into the axial channel of theapparatus absorb the heat from theliot gases passing through saidchannel and transmit it to the outside medium.`

The employment of Wires or ribbons to form the couples allow ofarranging a great quantity on a surface of determined dimensions.

The variations of the eleetromotive force of the battery in function ofthe mean internal temperature of the heated elements is indicated inFig. 5. The curve represents these variations.

The electromotive force expressed in volts is indicated by the abscissasand the mean temperature in Vdegrees centigradev by .the ordmates. Y

The variations of the di'erence of potential at the terminals of thebattery are shown by the curve u in Fig. 6; the abscissas indicate theintensities in milliamperes, andv to secure by Letters Patent of theUnited States is A thermo-electricv battery comprising a series ofsuperposed elements each constructed of wires or ribbons formed of twothermo-electric metals arranged radially and alternately and connectedsoas to form a Hat annular structure having gaps in the continuity of itsinner and outer periphery,

The curve o vindicates the difference` terminals on each of saide1ements,rannular washers arranged constructed of heat insulatingmaterial between individual elements of said series and coneentricallytherewith said Washers having such internal and external diameters thatthe inner periphcries of said elements lie slightly Within the A innerperipheries of said Washers and the outer peripheries of said elementsproject considerably beyond the outer peripheries of said Washers, meanselectrically connect.- ing the respective terminals of the elements,

a tapered tubular combustion chamber lying within the inner peripheriesyof said washers and elements, a cylindrical member of low heatconductivity within said combustion chamber and means connecting saidVelements and washers to form a rigid structure.

In witness whereof VI have signed this specification.

GABRIEL `DUCH

